My thoughts on villains are complicated, but also consider I liked Snape as an antagonist much better than Voldemort.

As far as protagonist and antagonist, I don't like to see them as good and evil (rotten, bad, whatever). Protagonist is the person who has a goal and is trying to accomplish a goal. The antagonist is someone whose goals are at cross-purposes to the antagonist. We generally want the protagonist to reach the goal, and the antagonist not to because it would preclude the protagonist from getting there.

But there's nothing about good or rotten in those definitions. Your protagonist's goal is to draw the reader in, be sympathetic in some way (even if a small one), and to drag the reader through the pages. If your rotten protagonist has an evil goal, your reader might be rooting for a loss. Unintended consequences might lead good things to come out of a rotten protagonist.

I'm in favor of trying it. If you can find something to draw readers, it will be popular whether or not you follow the 'good' side or the opposite.